The present invention relates generally to a taking apparatus comprising an imaging optical system and an electronic imaging device such as CCD or CMOS, and more particularly to a digital camera or a video camera capable of reproducing still pictures.
There has been an imaging apparatus known so far in the art, which makes use of an electronic imaging device such as CCD or CMOS, and converts an image formed through a taking optical system into electrical signals for recording, display, printing or other purposes.
Such imaging apparatus have now a lot more versions from a single-lens reflex camera adapted to take still pictures in a full-scale way to a compact camera designed to be readily carried around due to its compactness.
Of these, the so-called digital single-lens reflex camera incorporates an electronic imaging device of large size. This digital single-lens reflex camera, if it is used in combination of a large imaging plane with a taking lens having a reduced F-number, could have a particularly shallow depth of field so that artistic or sophisticated pictures can be obtained, and make it easy to check up a focus position through focusing by manual operation.
On the other hand, the compact camera is known to have pixels suitable for the taking and appreciation of still pictures. Such a compact camera is a camera system having a lot going for users who intend to mainly take common pictures without taking care of photograph arts or large posters or pictures for recording and appreciating purposes.
Among possible scenes taken, appreciated and enjoyed personally by common users, there would be time tables or other texts, map information or the events to be memorized, reminiscences or impression incidental to travels, events, etc., and the process of how children grow.
With the digital single-lens reflex camera, however, it is still difficult to downsize the whole system if the demanded image qualities and functions are factored in.
Among small-format electronic imaging device-incorporating imaging apparatus known so far in the art, there is a small-format video camera, or a compact digital camera mainly adapted to take still pictures. An imaging plane having a reduced area works for downsizing the whole size of the optical system, because even a taking lens having the same angle of view can have its focal length made short.
The former video camera of small size uses pixels only enough to maintain image quality during the taking of moving pictures or a limited number of substantial pixels, and so resolution per frame is insufficient and image quality is not worth still pictures as yet.
On the other hand, most compact digital cameras have pixels enough to take and appreciate common still pictures.
However, when it is intended to obtain pixels enough to allow for appreciation of good still pictures by use of a small-format electronic imaging device, the quantity of light sensed per pixel of the electronic imaging device tends to diminish and an exposure time tends to become long, rendering camera movement or subject movement likely to occur.
A limited imaging plane causes contrast to decrease under the influence of diffraction on the taking optical system and, hence, the image-formation capability of the taking optical system to become worse.